hubbard



March 17, 1942. w. A. HUBBARD 2,276,400

AIR HEATING DEVICE Filed Jan. l5, 1940 2 Sheets-Sheet l Effi/EXW March 17, 1942. w. A. HUBBARD 2,276,400

AIR HEATING DEVICE Filed Jan. l5, 1940 2 Sheets-Sheet 2 Patented Mar. 17, 1942 barren stares narrar orties AIR HEATENG DEVICE William A. Hubbard, Minneapolis, Minn.

Application January 15, 1940, Serial No. 313,381

5 Claims.

This invention relates to an air heater or a heat saving device and while said device may have various applications, it is particularly designed to be used with a furnace such as a furnace heated by an oil burner. Most domestic oil burners have been installed in furnaces originally designed for the use of coal or other solid fuel. In many of these installations there is insufficient llue travel to utilize the heat from the burning oil. With such an installation it is desirable to have an air heater so that the heat generated may be more efficiently used.

It is an object of this invention to provide an air heater of Asimple and eicient design adapted to be connected to the smoke pipe of a furnace and which may be used to heat the room in which the furnace isdisposed or to heat any other desired room or rooms.

It is a further object of the invention to provide a device comprising an elongated casing, a member in said casing comprising a series of conduits extending parallel to the axis of said casing and connected at their ends to Vform a circuitous passage through said member with reversely extending portions, one end of said member being connected to the smokepipe of a furnace and the other end being connected to a fan casing in said rst mentioned casing containing a fan adapted to draw the hot gases from the smoke pipe through said member, the discharge side of said fan casing being connected to said smoke pipe nearer the chimney than said rstmentioned conduit is connected, a second fan in said rst mentioned casing and a motor for` driving said fans whereby air is passed through said first mentioned casing over said member and is heated.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accomp'anying drawings inv which like reference characters refer to similar parts throughout the several views and in which:

Fig. 1 is a View partly in vertical section and partly in side elevation of the device;

Fig. 2 is a horizontal section taken on line 2 2 of Fig. 1 as indicated by the arrows;

Fig. 3 is a horizontal section taken on line 3-3 of Fig. 1 as indicated by the arrows;

Fig. 4 is a horizontal section taken on line 4--4 of Fig. l as indicated by the arrows;

Fig. 5- is a View in side elevation, some parts being broken away and others shown in vertical section illustrating the use of said device; and

Fig. 6 is a view in iront elevation, some parts being broken away and others shown in vertical section, said figure showing a modification.

Referring to the drawings, particularly Figs. 1 and 5, a furnace I0 is shown which may be of any ordinary fuel burning type, such as one containing an oil burner, said furnace having leading therefrom a smoke pipe Il through which the hot gases of combustion pass to the chimney I2. A portion of a thimble connection I3 is shown, tted into the opening in chimney I2 and into which pipe II passes. The device of the invention comprises an elongated casing I4 and while this casing might be of various forms, in the embodiment of the invention illustrated it is shown as cylindrical. Said casing comprises a shell Illa shown in Figs. 3 and 4 as made of two semi-cylindrical portions having outturned anges Illb connected by a plurality of headed and nutted bolts Ille. Shell Illa nts at its ends about flanges Md and Ille respectively formed on end plates Idf and Iig respectively. Plates M and IAQ are connected by a plurailty of circumferentially spaced rods l5, the same being shown as four in number, which rods are threaded at their ends and provided with nuts I6 above plate I 4f. At their lower ends rods I5 pass through plate Mg and through horizontal portions IIa of leg members I1. Nuts I8 are secured on the lower ends of rods I5, thus holding legs l1 firmly in place against plate Mg. Above plate Ilg sleeves I9 surround bolts |511 which also extend through plate Mg. A pair of bars 2o extend across casing I4 and are bored to have bolts IEa pass therethrough, said bars resting on sleeves I9. Above bars 2l) sleeves 2I surround rods I5 and a pair of bars 22 receive bolts I5a and rest upon sleeves 2l. Nuts 23 are threaded on bolts I5a and act to clamp bars 2D and 22 in place against sleeves I9 and 2| respectively.

A member designated generally as 24 is disposed in casing I4 and comprises a plurality of conduits 24a extending parallel to the axis of casing Ill and throughout a greater portion of the length thereof. Certain of the conduits 24a are connected at their tops and bottoms by elbows or U-shaped pipes 24h, so that member 24 h'as a continuous circuitous passage passing therethrough through the various conduits 24a., which passage has reversely extending portions or in other words portions extending upwardly and downwardly. One conduit Maa forms one end of member 24 and the same is connected to the inlet opening of a fan casing 25 supported upon the bars 22 and secured thereto by headed and nutted bolts 26 passing through lugs 25a at the top and bottom of casing 25 and through bars 22. A conduit 24ab forms the other end of member 24 and this conduit is connected to the smoke pipe II as shown in Figs. 1 and 5. The outlet of fan casing 25 is connected by a conduit 21 to the smoke pipe II at a point on the chimney side of conduit 24ab or at a point farther from the furnace I than is the conduit 24ab. Conduit 21 may be projected into the smoke pipe I I and have its end directed toward the chimney as shown in Figs. 1 and 5. The member 24 is supported in casing I4 by frame members 28 formed of iron bars or strips extending about the conduits 24a and also secured to the rods I5. 'Ihe casing 25 encloses a fan 29 mounted on a shaft 39 which extends through fan casing 26 and between the bars 22. A second fan 3| is secured to shaft 39 below bars 22 and between the same and bars 29. A motor 32 illustrated as of the electrical type is secured to bars 20 by bolts 33. It will be noted that casing I4 has an opening at its lower end surrounded by a flange I4h depending from plate I4g. Said casing also has an opening I4i at its upper end disposed centrally of plate I4f and a conduit 34 surrounds opening I4z` and has a flange 34a connected to the top of plate I4f by bolts 35. It will be understood that conduits 24ab and conduits 21 extend through plate |43 at one side of openin-g I4z' as shown in Fig. 2.

A pan 38 is supported in casing I4 preferably resting on the upper frame 28 and a similar pan 39 rests on the lower frame 28. Pans 38 and 39 will be of a shape to fit between the vertically extending conduits 24a. A pipe 40 connects with pan 38 some distance above the bottom thereof and is arranged to discharge into pan 39. A pipe 4I connects with pan 39 some distance above the bottom thereof and passes through the lower plate I4g so that it can be connected to some suitable drain. A pan 42 is preferably disposed below the opening in ange I4h.

With the furnace I D operating, hot gases will pass from the furnace through the smoke pipe Il to the chimney I2. Motor 32 will be supplied with current in the usual manner and will drive shaft 30, thus operating fans 29 and 3l. Fan 3| will preferably be arranged to force air upwardly. Fan 29 will exert suction through the member 24 and the hot gases of combustion will be drawn from smoke pipe II through conduit 241th and then successively through the conduits 24a until the gases pass through conduit 24aa into the fan casing 25. The gases will pass through this fan casing and be discharged therefrom through conduit 21 into the smoke pipe II. It will be noted that the gases passing through member 24 will be at somewhat reduced pressure or pressure below the pressure of the air in casing I4 so that there will be no leakage of these gases into the casing I4. There will thus be no odor from the furnace gases passing through member 24. It will also be noted that the withdrawal of the hot gases from the smoke pipe and their subsequent discharge thereinto will not in any way decrease or adversely affect the draft in smoke pipe I I. In fact by having the conduit 2'! arranged with its discharge directed toward the chimney, the draft may be increased. The fan 3| will cause movement of air through the opening within ange I4h and this air will pass upwardly around fan casing 25 and around the various conduits of member 24 and will pass out through conduit 34 at the top of casing I4. This air will be well heated in its passage through casing I4. The various conduits 24a give a very large surface for contact with the air so that the device has a high degree of efficiency as a heat exchanger. If the device is used to heat the room in which it is placed, the heated air may be delivered into said room from the top of casing I4. If it is desired to heat other rooms conduit 34 will be extended to such rooms. The cooler air is, of course, nearer the iioor and will usually be taken in through plate I4g. It will be understood, however, that fan 3| could move the air downwardly so that heated air would be discharged through the opening plate I4g. The device can also be used as a humidifier. Water will be placed in the pan 38 and this may be maintained at a desired level by a control device (not shown). The Water will run through conduit or pipe 40 into pan 39 and when it reaches a certain level in pan 39 will drain off through drain pipe 4I. The pan 42 is provided in case there should be any condensation within casing I4. It will be noted that the structure is quite simple and can be easily assembled. The conduits 24ar and the elbows 24b will all be of standard size and these can be easily assembled and economically replaced if necessary.

In Fig. 6 a slightly modified form of the invention is shown in which the structure is the same as in Figs. 1 to 5 except that conduit 24ac, corresponding to conduit 24ab in Fig. 1, is not connected to smoke pipe II. Instead a fuel burner 45, such as a gas or oil burner, is disposed in the conduit adjacent the bottom of conduit 24ac and will be supplied with fuel through the pipe 46. Burner 45 will be supplied with air drawn from the atmosphere as shown through the top of conduit 24de and the hot gases oi combustion from burner 45 will then be drawn through member 24 just as the hot gases from smoke pipe II are drawn therethrough in the form shown in the other figures. The pipe 21 will be connected to some suitable gas discharge means such as the smoke pipe II shown in Fig. 6.

From the above description it will be seen that I have produced a very novel and eiiicient air heater or heat saving device. The device is very compact and it is apparent that the same will have a high degree of utility for the purpose intended.

It will, of course, be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention, which generally stated, consists in a device capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

1. An air heating device having in combination, a casing comprising upper and lower end plates with cylindrical flanges extending towards each other, said end plates having openings therethrough forming inlet and outlet openings, a shell comprising semi-cylindrical members tting about and extending between said flanges and having outwardly and vertically extending mating flanges, means connecting said latter flanges for holding said shell in place, a plurality of rods extending between said end plates for clamping the same and said shell together, a frame at the lower end of said casing, a member disposed in said casing comprising a plurality of conduit convolutions and having an inlet pipe extending through the upper of said end plates adapted to be connected to a container of hot gases, a fan casing supported on said frame to which one end of said member is connected, a conduit extending from the discharge side of said casing through the upper of said end plates adapted to be connected to said container, a motor carried on said frame, a shaft connected to said motor, a fan in said fan casing driven by said shaft for drawing air through said member and a second fan on said shaft within said first mentioned casing for moving air through said casing.

2. An air heater constructed and arranged to be attached to the smoke pipe of a furnace having in combination, an elongated vertically extending casing having an inlet at its bottom and an outlet opening at its top, a device in said casing comprising a plurality of pipes extending in spaced relation therein for the greater part of the length of said casing, U-shaped members connecting the ends of said pipes to form a continuous conduit, a fan casing adjacent the bottom of said casing to which one end of said conduit is connected, a fan in said fan casing, the other end of said conduit extending through and beyond the top of said rst mentioned casing and connected to said smoke pipe, a pipe connected to the discharge outlet of said fan casing and extending vertically through the top of said first mentioned casing and connected to said smoke pipe, a second fan in said iirst mentioned casing below said fan casing for drawing air into said first mentioned casing to the inlet opening thereof and forcing it out through said outlet opening of said first mentioned casing, said air passing around said device and a motor below said last mentioned fan for driving both of said fans.

3. The structure set forth in claim 2, vertically spaced bands extending about said pipes for supporting the same and means at the sides of said rst mentioned casing for supporting said bands.

4. The structure set forth in claim 2, vertically spaced bands extending about said pipes for supporting the same, means at the sides of said first mentioned casing for supporting said bands, a shallow annular pan supported upon each of said bands and extending about said pipes, a conduit extending from adjacent the top of the upper pan to adjacent the bottom of the lower pan and a conduit extending from adjacent the top of the lower pan through the bottom of said first mentioned casing.

5. The structure set forth in claim 2, said last mentioned pipe being connected to said smoke pipe at the chimney side of said other end of said conduit and having its terminal directed longitudinally of said smoke pipe in the direction of travel of the gases to the chimney.

WILLIAM A. HUBBARD. 

